The present invention relates generally to improvements in writing instruments and it relates more particularly to an improved writing instrument having multiple writing units, at least one of which is a mechanical pencil having a propel-repel mechanism.
There are many types of multiple unit writing instruments which have been heretofore available and proposed in which a selected writing element may be protracted with the retraction of the other writing elements. Such writing instrument which is highly satisfactory is disclosed in U.S. Pat. No. 3,266,465 granted Aug. 16, 1966 to W. C. Ganz. However, the aforesaid writing instrument employs writing elements such as of the ball point type which require no individual adjustment. A well known type of adjustable writing element employs a pencil lead and includes a spring retracted axial plunger the depression of which releases and advances the lead and the retraction of which locks the lead in its advance position. This mechanical pencil writing element of its propel-repel type cannot be conveniently employed with the aforesaid multiple unit writing instrument and although multiple unit writing instruments have been available in which one of the writing elements is a propel-repel pencil element, these instruments are generally complex and unreliable, of little versitility and adaptability and otherwise leave much to be desired.